YouGovPolimetrix just released a metric ton of senate polls. Be very, very warned, though: YouGov polls on the Internet. We've generally derided this methodology in the past (take a look at Zogby's absurd "Interactive" polls), so consider this strictly for fun.
Arkansas
Lincoln (D-inc) 37%, Baker (R) 37%
Lincoln (D-inc) 39%, Hendren (R) 37%
Lincoln (D-inc) 38%, Coleman (R) 34%
Lincoln (D-inc) 37%, Cox (R) 36%